The period between harvesting an organ and transplantation of the organ or cells from the organ into the recipient usually involves cold storage and transportation. During this period, the supply of blood, and consequently oxygen, is cut off from the organ. This period of cold ischemia is, at present, unavoidable and results in the gradual deterioration of cell function, eventually progressing to irreversible damage.
A new rapidly emerging technique for improved preservation of donor pancreata and possibly other organs has been established and several groups are now testing it in research and clinical trials. The technique is called the 2 layer method and calls for the utilization of a solution of perfluorocarbon (PFC) or other oxygen-dissolving solution in combination with a cold storage preservation solution such as the University of Wisconsin preservation solution (the “UW solution”). The UW solution contains as its primary agents lactobionate and raffinose. These compounds are too large to enter the cells and therefore remain in the extracellular spaces. These impermeants act through osmotic forces to prevent cell swelling that would otherwise damage the stored organ.
Liver is another common organ for transplantation, as transplantation can be the only option for many patients suffering from treatable liver diseases. A successful transplantation requires that the donor liver be optimally preserved. Although the liver can be preserved for 10-20 h, its cellular energy levels fall to critically low values within the first 1-4 h. The consequences of a poorly functioning transplanted liver are potentially fatal, and requires retransplantation at a significant increase in cost. It is therefore vital that adequate procedures and systems be provided for organ storage and transportation.
It is a well known fact that maintaining an organ partially submerged in oxygenated PFC greatly extends its useful life for transplantation or for cell procurement. The density of most organs is approximately 1 g/cm3. The density of PFC is approximately 2 times that of the organ or 1.95 g/cm3 and the density of the UW solution is approximately equal to that of the organ. Accordingly, the PFC settles at the bottom of the container while the UW solution settles on top of it. The organ typically rests partially submerged in the PFC while also being contacted by the UW solution. It is difficult to maintain this partial submersion especially during transportation of the organ because of the different sizes and shapes of organs and because the position of the container may also change.
Walsh, U.S. Pat. No. 6,490,8890, discloses a regulated organ containment shipping system using dual-layer preservation liquid. The organ containment shipping system has an outer container adapted to receive a passive cooling medium and an inner container positioned within the outer container by structure that includes a gimbal mechanism to substantially maintain the inner container in a predefined orientation in the event of a change of orientation of the outer container.